1ELECTRICAL SAFETYPart 2 Working Safely 2ELECTRICITY - THE DANGERSSHOCK BURNS ARC FLASH FALLS 3ELECTRICAL SHOCKAn electrical shock is a current flow through the body. The shock occurs when any part of your body completes a circuit by being In contact with two wires In contact with a wire and ground In contact with a metal part that is in contact with a wire in a circuit and ground. 4ELECTRICAL SHOCKThe response could range from a faint tingling sensation to death. You can perceive a currentas low as 1 milliamp. At 5 mA you will feel a slight shock. Most people can let go. 5ELECTRICAL SHOCKCant Let Go Current 10 mA to 30 mA Painful shock and sustainedmuscle contraction. 6ELECTRICAL SHOCK50 mA to 150 mAExtreme pain, respiratory arrest, severemuscle contractions, possible death1,000 mA to 4,300 mA Ventricular fibrillation, muscle contractions, nerve damage, deathlikely. 7ELECTRICAL SHOCK 8ELECTRICAL SHOCKThe duration and the amount of current affect the severity of an electrical shockinjury. Death can occur in 2 seconds with a current of 0.1 amps (100 milliamps). 100 mA for 3 seconds is as dangerous as 900 mA for 0.03 seconds. 9ELECTRICAL SHOCKOther factors that may affect the severity of the shock are The voltage of the current. The presence of moisture. The phase of the heart cycle when the shock occurs. The general health of the person prior to the shock. 10ELECTRICAL SHOCKHigh voltages increase shock injuriesbecause a higher voltage produces agreater current.I E/R Resistance - the lower the resistance, thegreater the current will be.R E/I 11ELECTRICAL SHOCKResistance between major extremities of an average human body is 1,500 ohms hand to hand or hand to foot. If you grabbed a wire carrying 120 volts alternating current how much current would flow through your body?I E/R 12ELECTRICAL SHOCK PATHWAYS2. Right foot left foot path1. Right hand left hand4. Left hand left foot path3. Right hand right foot path 13ELECTRICAL BURNSElectrical burns are the result of heat generated by the flow of electric current through the body. The dark spot is where thecurrent entered the body. 14ELECTRICAL BURNSElectricity arced through the air as a result of a power box explosion. The arc was drawn to this mans arm pits because of perspiration. 15ELECTRICAL BURNSCurrent exited this man at his knees, catching his clothing on fire and burning his upper leg. 16ELECTRICAL BURNSThe current exited the foot of this man. Because of severe internal injuries, the foot had to be amputated a few days later. 17ELECTRICAL BURNSThis worker was shocked by a tool he was holding. A few days later. 18ARC FLASHAn arc flash is a shortcircuit through the air. It can occur if a conductiveobject gets too close to ahigh-amp current sourceor by equipment failure such as opening orclosing disconnects. 19FALLSWorkers who get shocked while on a ladder or other elevated location can fall, resulting in serious injury or death. 20ELECTRICAL HAZARDSElectrical shocks, fires or falls can result from Improper grounding Improper PPE Improper tools Overloaded circuits Exposed electrical parts Overhead power lines Inadequate wiring Defective insulation Wet conditions 21ELECTRICAL HAZARDSExposed Electrical Parts 22ELECTRICAL HAZARDSOverhead Power LinesNIOSH Case Study Untrained worker raising a 21 foot fence rail under a 7,200 volt power line. Worker was electrocuted. 23ELECTRICAL HAZARDSInadequate WiringWire Gauge - wire size or diameter Ampacity - the maximum amount of current a wire can carry safely without overheatingIncorrect wiring practices can cause fires! If you touch live electrical parts, you will be shocked. Overloaded wires get hot! 24ELECTRICAL HAZARDS Copper Wire Ampacity Table Wire Gauge Maximum Ampacity 14 15 12 20 10 30 8 45 6 65 4 85 2 115 0 150 2/0 175 4/0 250 25ELECTRICAL HAZARDSDefective Insulation 26ELECTRICAL HAZARDSDefective InsulationScrew penetrated insulation creating a small arc flash. 27ELECTRICAL HAZARDSWet ConditionsWet clothing, high humidity, and perspiration also increase your chances of being electrocuted. 28ELECTRICAL HAZARDSImproper grounding 29ELECTRICAL HAZARDSImproper grounding 30ELECTRICAL HAZARDSOverloaded CircuitsToo much current in a circuit can lead to a fire or electrical shock. 31THE REGULATIONSCalOSHA Low voltage (600V) Electrical Safety Orders Article 3, 2320.1 Only qualified persons shall work on electrical equipment or systems. A qualified person is defined as a person designated by the employer, who by reason of experience or instruction has demonstrated familiarity with the operation to be performed and the hazards involved. 32THE REGULATIONS

2320.2

Work SHALL NOT be perform on energized parts of equipment or systems until the following conditions are met

Responsible supervision has determined that the work is to be performed while the equipment or system are energized.

Involved personnel have received instructionson the work techniques and hazards involvedin working on energized equipment.

Approved insulated glovesshall be worn for voltages in excess of 250 volts to ground.

34THE REGULATIONS

2320.2 (contd)

Suitable barriers or approved insulating material shall be provided and used to prevent accidental contact with energized parts. 6. Suitable eye protection has been provided and used.

35THE REGULATIONS

2320.2 (contd)

Where required for personnel protection, suitable barricades, tags, or signs are in place.

36THE REGULATIONS

2320.2 (contd)

Each employee who is exposed to the hazardsof flames or electric arcs wears apparel that, when exposed to flames or electric arcs, does not increase the extent of injury that would be sustained by the employee.

37THE REGULATIONS 2320.3All electrical equipment and systems shall be treated as energized until tested or otherwise proven to be de-energized. 38THE REGULATIONSGeneral Safety Orders 3314 (g) A hazardous energy control procedure shall be developed and utilized by the employer when employees are engaged in the cleaning, repairing, servicing, setting-up or adjusting of prime movers, machinery and equipment. LOCKOUT/TAGOUT 39LOCKOUT/TAGOUTOverview of Procedures Must use own lock and keep key on his/her person until job is done. Procedures apply to all Sources of energy - electrical, thermal, hydraulic, pneumatic, mechanical, etc. 40LOCKOUT/TAGOUTNotify all affected employees. Identify all applicable isolating devices - breakers, switches, valves, etc. 41LOCKOUT/TAGOUTObtain a padlock and tag from lockoutstation. Isolate source of power at the circuit breaker on MCC paneland at other sourcesof hazardous energy. 42LOCKOUT/TAGOUTOn the tag, write name, date, time and why equipment is locked out. BLOCK DRAIN BLEEDTEST Test to be sure there is no release of hazardous energy. 43LOCKOUT/TAGOUT Always take precautions to guard against the possibility of faulty switches or short circuits when locking out equipment. Test the equipment with a meter when doing electrical work. 44THE REGULATIONSDo not use conductive measuring tapes or ropes when working near energized parts of equipment. Legibly mark each motor controller to indicate the motor it controls and provide a corresponding marking on each motor. When a circuit is discontinued, remove the conductors from the raceway or treat the circuit as if it is in use. 45THE REGULATIONSDo not use conductive fish tape in raceways entering enclosures with exposed energized parts unless the parts are isolated by barriers. At least 3 feet of cleared space (no storage) shall be available in the direction of access to control panels, circuit breakers, switchboards, fused switches, and similar equipment. 46THE REGULATIONSAll electrical equipment shall have markings giving voltage, current, wattage, or other ratings. Circuit breakers shall clearly indicate whether they are in the open off or closed on position. 47THE REGULATIONSFlexible cords or cables SHALL NOT be used as a substitute for fixed wiring of a structure, where run through holes in walls, ceilings or floors, where run through doorways, windows or similar openings, where attached to building surfaces, or where concealed behind building walls, ceilings or floors 48THE REGULATIONSFlexible cords shall be used only in continuous lengths without splice or tap. Hard service flexible cords No. 12 or larger can be spliced as long as the splice retains the insulation, outer sheath properties, and usage characteristics of the cord. 49GROUND FAULT CIRCUITINTERRUPTERUse a GFCI when working on circuits or using electrical equipment in damp or wet areas. 50DOUBLE INSULATED TOOLSUse double insulated toolsif GFCI is not available.Always check cord and plug on all power tools before use 51ELECTRICAL FIRESNEVER put water on an electrical fire. Use Class C or ABC fire extinguishers. 52THE REGULATIONSWrist watches, rings, or other jewelry should not be worn while working with or around machinery with moving parts in which such objects may be caught, or around electrically energized equipment.BE SAFE ! 53THE END

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